Incidence of systemic connective tissue diseases in children: a nationwide prospective study in Finland.

Abstract

CTD and S-JA are rare before the age of 16 years. From the present incidence figures and those recently published for JA the incidence of CTD is estimated to be between 4 and 7% of that of JA, and S-JA accounts for only 2 to 4% of all JA.